POS0439 SCREENING FOR PLASMA BIOMARKERS PREDICTING RADIOGRAPHIC PROGRESSION IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS: A PRELIMINARY STUDY
Authors: J. Baloun, K. Bubová, A. Pekacova, L. Ondrejčáková, V. Červeňák, M. Gregová, S. Forejtova, J. Horinkova, J. Gatterova, M. Tomčík, J. Vencovský, K. Pavelka, L. Šenolt
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Axial spondyloarthritis (AxSpA) is an immune-mediated rheumatic disease that has a significant impact on a patient's quality of life. Therefore, early diagnosis and recognition of patients with potentially rapid structural progression of the disease are of great importance. <h3>Objectives</h3> This study aimed to investigate proteomic data in patients' plasma to discover candidate biomarkers differentiating axSpA patients with radiographic progression after two years. <h3>Methods</h3> A cohort of 20 patients with axSpA was selected based on the radiographic progression for the purpose of this preliminary study. Baseline and two-year radiographs of the cervical and lumbar spine were independently assessed by two blinded readers using modified Stoke Ankylosing Spondylitis <i>Spine</i> Score (mSASSS). No radiographic progression and significant radiographic progression were characterized as a change in mSASSS ≤0 and &gt;2, respectively, from baseline to year two. Disease activity was determined using C-reactive protein (CRP), Ankylosing Spondylitis Disease Activity Score (ASDAS) and Bath Ankylosing Spondylitis Activity Disease Activity Index (BASDAI). The proteome of the plasma samples was profiled using liquid chromatography with tandem mass spectrometry detection, and the difference in protein concentration was evaluated using linear mixed-effects modelling. <h3>Results</h3> Our cohort included ten patients without radiographic spinal progression (mean±SD age 34.9±9.0 years, 40% female) and ten patients (mean±SD age 40.8±9.0 years, 40% female) who developed the progression after two years (mean±SD change in mSASSS 9.88±5.1). Additionally, of all included patients, 14 were classified as radiographic axSpA (mean±SD age 36.9±8.6 years, 28.6% female) and six as non-radiographic axSpA (mean±SD age 40.2±9.2 years, 66.7% female). The high-throughput profiling of plasma proteome detected 489 quantifiable proteins and our statistical analysis revealed 30 proteins with different concentrations between patients without and with radiographic progression (p&lt;0.05 for all). Out of these proteins, haptoglobin (1.76-fold, p&lt;0.001) and serum amyloid P-component (SAP) (1.57-fold, p&lt;0.001) were upregulated, while gelsolin (1.23-fold, p = 0.001) was downregulated in patients with mSASSS progression compared to those without radiographic progression (Figure 1A). In addition, all these proteins significantly correlated with mSASSS, CRP or ASDAS (Figure 1B). However, after adjustment for CRP, only SAP and gelsolin, which were previously associated with axSpA<sup>[1,2]</sup>, were independently associated with structural progression. <h3>Conclusion</h3> We identified two plasma proteins with the potential to independently predict the radiographic progression of axSpA. Further studies in a larger cohort of patients are needed to validate these data. <h3>References</h3> [1]Lee, J. H. <i>et al.</i> Proteomic analysis of human synovial fluid reveals potential diagnostic biomarkers for ankylosing spondylitis. <i>Clin. Proteomics</i><b>17</b>, 1–11 (2020). [2]Genre, F. <i>et al.</i> Gelsolin levels are decreased in ankylosing spondylitis patients undergoing anti-TNF-alpha therapy. <i>Clin. Exp. Rheumatol.</i><b>32</b>, 218–24 (2014). <h3>Acknowledgements</h3> This work was supported by SVV 260 523, BBMRI-CZ LM2018125, and MHCR No. 023728. <h3>Disclosure of Interests</h3> None Declared.